My then 6 year old skipped midyear from 1st to 2nd, against the will of the principal. The skip evaluation team ganged up on him and forced it :-) (including the current teacher, the receiving teacher, the district psychologist and her intern, and us parents). The principal was appalled but agreed to go along, swearing it wouldn't work and we'd be back in two weeks.
It couldn't have been any more perfect. Receiving teacher was delighted, extremely tall 6 year old son fit in perfectly. He met new friends, finally found kids he got along with and it was a magical solution.
Of course, it was temporary because the vindictive principal was out for revenge. He soon made it very clear that the skip was all we were getting, no matter what and that there would be no further meetings, differentiation or accommodations. So when, even post-skip, my son had exceeded the math curriculum and needed further subject acceleration, we were refused.
So, socially it was perfect, academically it was perfect for a year, and now we're homeschooling for subject acceleration.
I think the very best advice I have ever received on this issue was to plan one year at a time, for the least worst option. It sounds doom and gloom, but you get a lot less disappointment!
